Various electrical codes require the installation of a secondary grounding conductor between electrical conduits and metal enclosures. These grounding requirements are set forth in Section 250 of the National Electrical Code (“NEC”), which requires the effective grounding path to be permanent and electrically continuous. To comply with the codes, various grounding devices have been attached to the fittings that connect conduits to electrical enclosures. Examples of such devices are found in U.S. Pat. No. 2,974,185 to Curtiss and U.S. Pat. No. 3,492,625 to Bromberg, both of which disclose grounding connections attached to conduit bushings and both of which are incorporated herein in their entirety.
Several of the grounding devices currently being used are designed with a grounding connection permanently attached to a bushing at one or more predetermined locations. In these devices, the grounding lugs are mounted to the bushing via a tapped hole and bolt. The electrician would be limited to mounting locations by the number of tapped holes around the perimeter of the bushing (usually 2 or 3, see U.S. Pat. No. 3,492,625). Although these devices are functional in design, they often present installation problems for the user. Specifically, when the grounding connection is permanently attached to the bushing, the installer cannot control the final angular position of the grounding connection relative to the conduit once the bushing is tightened. Thus, the grounding connection may not be positioned at an accessible location after the bushing is tightened. The user must, therefore, overtighten or undertighten the gland nut to locate the grounding connection at a suitable angular position. As will be appreciated by those skilled in the art, overtightening or undertightening may affect the integrity of the seal between the conduit and the wall of the enclosure. The location of the grounding connection on the bushing may also make tightening the bushing difficult and/or infeasible in applications where the space is restricted.
There is, therefore, a need for a bushing with a grounding connection which can be oriented over 360 degrees and which does not interfere with the tightening of the bushing. There is also a need for a bushing with a grounding connection which can be easily installed in enclosures with limited room for tightening the bushing.